This invention is in the field of products used for nutrition and care of plants and flowers. Specifically, this invention is in the field of monitoring the application of treatment products applied to cut flowers.
The business of harvesting and supplying cut flowers from growing point to markets all over the world has created the need for treatment products that are applied to the water that the cut flowers are placed in. These treatment products prolong the life of the cut flowers and make it possible for the cut flowers to be shipped all over the world from their place of being grown to their final delivery point and arrive in saleable condition.
Cut flower treatment products are usually sold as concentrates and as such they are added to water in a certain concentration after which the cut flowers are placed in this mixture of water and product. Cut flower treatment products can also be sold as ready to use solutions.
The intended effects of the treatment products are many and varied. Some of the treatment products are designed to curtail ethylene production by the flowers, or reduce the sensitivity to ethylene of the flowers. Other treatment products are designed to decrease leaf yellowing and/or decrease microbial growth in the flower water and flower stem and/or decrease flower stem growth and/or stimulate water uptake. In addition, other treatment products can provide the flowers with nutrition for better development. The general flower quality, as measured by such criteria as vase life and/or leaf quality and/or flower quality, is improved by using these treatment products.
The cut flower treatment products can be used anywhere in the post-harvest chain of the flowers. Cut flower treatment products can be used by growers, auctions, bouquetmakers, supermarkets, florists and individual consumers. In the post-harvest chain of cut flowers several treatment products can be used consecutively, while combination of two or more products at one time is also possible. The duration of the treatment may vary from xe2x80x9cquick dipsxe2x80x9d of about 10 seconds up to longer xe2x80x9ctransport treatmentsxe2x80x9d which can last for many days. Many of the treatment programs are described as being short xe2x80x9cpulse treatmentsxe2x80x9d of about four hours.
In order to ensure that the cut flowers remain fresh and in saleable condition, it is important that the proper amount, usually referred to as xe2x80x9cdosagexe2x80x9d of treatment product is applied. Incorrect dosage can lead to serious problems. Overdosage may result in phytotoxicity symptoms in the cut flowers and consequently decrease instead of increase their vase life; moreover, the environment is exposed to more active ingredients than required in this case. In the case of underdosage, suboptimal results will be obtained as the flowers are exposed to an insufficient amount of active component(s). In the case of microbial growth, underdosage might even result in adverse effects as non anti-microbial ingredients in the products are then likely to stimulate microbial growth.
Dosage of the treatment products can be done by hand or by automation (i.e. dosing units). Dosages typically range from 0.05-3%, based on volume of treatment product and volume of cut flower water, but can also lie outside this range. Current practice includes checking the dosage based on measuring the level of an active component (i.e. aluminum sulfate, silver, amino-oxy-acetic acid) in the ready-to-use solutions and in samples thereof. In some cases instead of an active component a metal tracer (i.e. manganese) is being used for dosage control. Current methods of measuring these substances have one or more of the following problems: the analytical methods use bulky and costly equipment, interferences from other components present undermine the precision and accuracy of the analytical method, the methods are time-consuming, labor-intensive analyses that are not compatible with continuous monitoring and need to be carried out in a laboratory environment, and it is quite common for there to be degradation or deposition of active components resulting in inaccurate readings.
It would be desirable to have a simpler, less costly, more flexible analytical method that would enable the amount of treatment product present in said water that cut flowers are placed in to be measured.
This invention is a method to determine whether the desired amount of treatment product is present in water that cut flowers are placed in; comprising the steps of:
a) adding a known amount of an inert fluorescent tracer to a known amount of treatment product, with said treatment product being suitable for application to water that cut flowers are placed in;
b) applying said treatment product to water that cut flowers are placed in;
c) using a fluorometer to measure the fluorescent signal of said inert fluorescent tracer in said water that cut flowers are placed in; and optionally,
d) adjusting the amount of treatment product applied to said water that cut flowers are placed in, based on the measured fluorescent signal of said inert fluorescent tracer.